Racket stringing apparatus



Jan. '23, 1940.

E. H. SERRANO RACKET STRINGING APPARATUS Filed Oct. 14, 1958 E H Serran0 2 Sheets-Sheet 1 Patented hm. 23, 1940 UNITED STATES PATENT OFFICE 6Glaims.

This invention relates to certain new and useful improvements in racketstringing apparatus.

The primary object of the invention is to provide racket stringingapparatus wherein the 5 string frame of the racket is supported duringthe stringing operation with the handle of the racket free of supportwith liability of damaging or marring the handle of the racketeliminated.

A further object of the invention is to provide racket strinkingapparatus wherein a movably mounted weight is asociated with the stringtensioning device and is adjustable to vary the tension imparted to thestrings with clamps engageable with the strings for holding sections ofthe strings under tension during the stringing of the racket.

With the above and other objects in view that will become apparent asthe nature of the invention is better understood, the same consists inthe novel form, combination and arrangement of parts hereinafter morefully described, shown in the accompanying drawings and claimed.

In the drawings:

Figure 1 is a side elevational view, partly broken away and shown insection of racket stringing apparatus constructed in accordance with thepresent invention and illustrating the adjustable weighted memberassociated with the string gripping and tensioning device;

Figure 2 is a top plan View;

Figure 3 is a fragmentary end elevational View, partly broken away andshown in section and showing the string gripper of the tensioning de- Jvice;

Figure 4 is a detail sectional view taken on line 4-4 of Figure 1 withthe string clamps removed from the longitudinal supporting bars andmounted upon the laterally extending supporting bars and illustratingthe slidable mounting of the later supporting bars;

Figure 5 is a horizontal sectional view taken on line 5-5 of Figure 1; 1

Figure 6 is a fragmentary-side elevational view of part of the mechanismof the string tensioning devices, and

Figure 7 is a vertical longitudinal sectional view of the dash-potdevice associated with the weighted lever of the string tensioner.

Referring more in detail to the accompanying drawings, the referencecharacter Ill designates a tubular column or post supported at its lowerend by a base plate I! and carrying a head at the upper end thereof forthe support of a racket to be strung while devices for effecting thestringing of the racket and the tensioning of the strings are associatedwith the post and head.

The upper end wall l2 of the tubular post II] has pivotally attachedthereto by means of the pivot pin I 3, one end of an elongated plate I 4that is movable in a horizontal plane, the other end of the plate M thatextends laterally of the tubular post I having a block l rigid with theupper face thereof and from which block an arm l6 extends in an upwardlyinclined direction as shown in Figure 1 in overlying relation to theplate I4, the upper free end of the arm being constructed and arrangedfor the support of a portion of the racket frame. As shown in Figure 1,a pair of gripping jaws I1 is carried by the upper free end of the armI6 for engagement with the throat portion of a racket, the handle of theracket being designated by the reference character l8 and the stringframe thereof being shown at H), the jaws I! being moved into grippingengagement with the throat of the racket by means of the thumb screw 20.

A rectangular opening extends longitudinally of the block l5 for thereception of one end of an elongated bar 22 of the same configuration incross-section as the opening 2|, the bar being slidably mounted in saidopening and retained in adjusted position by means of the set screw 23.A racket frame supporting arm 24 similar in design to the arm l6 carriedby the block 2| is mounted as at 25 upon the adjacent end of the bar 22,the upper free end of the arm 24 having racket frame gripping jaws 26moved into clamping engagement with a racket frame by means of the thumbnut 21 as shown in Figure 1. 5

As shown more clearly in Figures 1 and 3, diametrically oppositehousings 28 are carried by the upper end of the tubular post [0 adjacentthe upper end wall I2 while a rod rectangular in cross-section and shownby the reference character 29 extends through said housings 28 and theupper end of the post In, anti friction bearings 30 being provided inthe housings 28 to facilitate sliding movements of the rod 29 and forthe reduction of friction. The end of the rod 29 adjacent the racketsupporting arm 24 is laterally offset as shown at 3| for the rigidsupport of an upstanding string puller arm 32 that carries upon itsupper end a vertically adjustable drum having side flanges 33 with arubber band 34 surrounding the drum and engaged at its side edges withsaid flanges 33. The drum is mounted upon the upper end of the arm 32and the string 31 to be placed under tension is wrapped around therubber band 34 on the drum with the end of the string positioned betweena side edge of the rub her band and an adjacent side flange 33 on thedrum as shown in Figure 2.

To place the racket string 31 under tension during the stringing of theracket frame E9, the rod 29 carrying the string puller arm 32 is shiftedtransversely of the upper end of the tubular post Ii! in a directionaway from the racket supporting arm K6, the devices for effectingmovement of the rod 29 including a shaft 38 shown in Figure s as beingjournaled at its ends in the sidewalls of the tubular post it adjacentits upper end for the rotatable support of a pair of spaced combinationsheaves and sprocket wheels, each of which includes a sheave wheelsection 39'and a A sprocket chain M longitudinally extending slot :46 inthe side wall of the tubular post it diametrically opposite the pivot45, the extended end of the arm M being graduated as at t? and carryingat its outer free end weights 48 that are adjustable on the arm by theanchor screws 48 to vary the force of leverage thereof.

A rectangular treadle frame including side rods'49 and end rods 56 and51 incloses the lower end of the tubular post it, the treadle rod? 5ibeing pivotally supported in upstanding lugs 52 carried by'the'baseplate It while a cross rod 53 extending between and rigid with the siderods 49 of the treadle frame works in arcuate slots 54 in side walls ofthe tubular post N3, the rod 58 of the treadle frame constituting theoperating end thereof. As shown more clearly inFigures l, 3 and 5, theweighted arm' 44 in the end thereof within the tubular post' itis'provided with a longitudinally extending slot 55 through which a pinfili'extends, each projecting end of the pin 55 having one end of acable El attached thereto, the cable 5'! extending over an adjacentsheave wheel 39 and directed downwardly for attachment at its lower endasat 58to'the upper end of a. link 59 rising from the'cross-rod 53 ofthe treadle frame. To tension a string 37, the treadle frame rod 50 islowered by foot pressure thereon, such movement exerting a pull on thecables 5'! attached to the arms 58 for raising the weighted end of thearm 44, such movement placing slack in the chain l! so that the rod 29carrying the string clamp puller arm 32 may be shifted to the desiredposition for engagement with the string 31. When pressure of the treadlerod 58 is relieved, the arm M is lowered by the weights 48 for reverselyrotating the combination sheave and sprocket wheels to cause the chainsll to wind onto the sprocket wheels 40 and to exert a pull on the rod 29with the string clamp arms 32 placing the string 3'! under the desiredtension. To cushion the descending movement of the weighted end of thelever arm 44 to relieve sudden strains on the racket string 31, there isprovided a dash-pot construction shown in Figures 1 and 7 as comprisinga fluid cylinder 44 pivotally mounted at its lower end as at 35 on abracket 46 projecting laterally of the tubular post it below the leverarm 44, the fluid cylinder 44 extending upwardly and substantiallyparallel with the tubular post Ii] beneath the lever arm 44 exteriorlyof said tubular post. A ported piston 41- is reciprocably mounted in thefluid cylinder 44 and is carried by the lower end of a piston rod 48*extending through the piston 41 and carrying a movable disk valve 49upon its lower end cooperating with the ported piston. A vented plug 50*is mounted in the upper end of the fluid cylinder M and through whichthe piston rod 48 slidably extends, the upperend of the piston rod 18carrying a clevis di that is pivotally attached as at 52 to the leverarm 44 inwardly of the graduations 41 on said lever arm. Fluid of asuitable character and indicated by the referencecharacter 53 in thecylinder 44 retards reciprocatory movements of the ported piston 4'! andoperates to effect a smooth and even pivotal movement of. the lever armM in the absence of all jerky or vibratory movements of said arm andfor'an even pull on the racket string 31. The weights" 48 are adjustableonthe arm 44 to the desired position indicated by the arm'graduationst'l for placing the string 31 under the desired tension.

String clamps are provided for holding a string under tension while theplate it is being shifted on its pivotal mounting 53 for placing theracket frame 59' in a position relative to the string clamp puller arms32 for the tensioning of the succeeding string section of the racketframe and as shown in Figures 1 and 2, a rod 60 projects laterally ofeach side of the block 55 to receive a sleeve 8! carried by one end ofva rod 32 positioned parallel with the bar 22. the upper and lower edgesof the bar 22 are provided with guide grooves 63 to receive edge flangesof a pair of sliding blocks 64% with a block disposed at each side ofthe bar 22, the assembly of the blocks 64 on the bar 22 permittingunobstructed passing movements relative to each other. An outwardlydirected rod 65 is carried by each sliding block 64. The stringclamp-com prises a pair of arms 66 moved into clamping position relativeto each other by means of. the cam and handle :device 61', the lowerends of the arms 56 being provided with clamp elements 68 for engagementwith the-rods 62 and 65 while the upper ends-69 of the arms 6% arefashioned for engagement with a racket string and to provide clearancefor cross strings. As shown in Figure 1, the sliding blocks E i areretained in adjusted positions on the bar 22 by means of the set screw10.-

From the above detailed description of; the invention, it is believedthat the construction andoperation thereof will at once be apparent andwhile there is herein shown and described the preferred embodiment ofthe invention, it is nevertheless to be understood that minor changesmay be made therein without departing from the spirit and scope of theinvention as claimed.

I claim:

1. In a racket stringing apparatus, wherein a racket supporting head ismounted upon the upper end of a standard, and wherein the string istensioncd by sections with a tensioned string section held under tensionwhile tensioning another section; string tensioning means including astring puller slidably mounted on the upper end of the standard formovements transversely thereof, a drum having a cushion surface carriedby the puller adapted to have the racket string wound thereon, anadjustably weighted lever arm pivotally mounted on the standard, op-

As shown in Figure 4.

erative' connections between the string puller and lever arm foroperating the string puller to place a string under tension, a dash potconnection be tween the lever arm and standard for retarding movementsof the lever arm during pulling force thereof on the string puller andmanually operable means in said operative connections for rendering thelever arm and string puller inoperative.

2. In a racket stringing apparatus, wherein a racket supporting head ismounted upon the upper end of a standard, and wherein the string istensioned by sections with a tensioned string section held under tensionwhile tensioning another section, string tensioning means including astring puller slidably mounted on the upper end of the standard formovements transversely thereof, a drum having a cushion surface carriedby the puller adapted to have the racket string wound thereon, tnadjustably weighted lever arm pivotally mounted in the standard,operative connections between the string puller and lever arm foroperating the string'puller to place a string under tension, a dash potconnection between the lever arm and standard for retarding movements ofthe lever arm during pulling force thereof on the string puller andmanually operable means in said operative connections for rendering thelever arm and string puller inoperative, the string puller including arod slidable in the standard, the operative connections including aflexible element attached at one end to the slide rod, a rotatablemember on the standard to which the other end of the flexible element isattached and a flexible connection between the lever arm and rotatablemember.

3. In a racket stringing apparatus, wherein a racket supporting head ismounted upon the upper end of a standard, and wherein the string istensioned by sections with a tensioned string section held under tensionwhile tensioning another section, string tensioning means including astring puller slidably mounted on the upper end of the standard formovements transversely thereof, a drum having a cushion surface car riedby the puller adapted to have the racket string wound thereon, anadjustably weighted lever arm pivotally mounted in the standard,operative connections between the string puller and lever arm foroperating the string puller to place a string under tension, a dashpotconnection between the lever arm and standard for retarding movementsof the lever arm during pulling force thereof on the stringpuller andmanually operable means in said operative connections for rendering thelever arm and string puller inoperative, the string puller including arod slidable in the standard, the operative connections including aflexible element attached at one end to the slide rod, a rotatablemember on the standard to which the other end of the flexible element isattached and a flexible connection between the lever arm and rotatablemember, and the manually operable means including a lever frame attachedto one end of the flexible connection between the lever arm androtatable member.

4. In a racket stringing apparatus, wherein a racket supporting head ismounted upon the upper end of a standard, and wherein the string istensioned by sections with a tensioned string section held under tensionwhile tensioning another section, string tensioning means including astring puller slidably mounted on the upper end of the standard formovements transversely thereof, and a slide rod movable therewith, awheel journaled in the upper end of the standard, a flexible elementanchored at one end to the rod and anchored at its other end to thewheel to be partly wound thereon and means for rotating the wheel towind the flexible element thereon to move the rod and string puller forplacing a string under tension, including an adjustably weighted leverarm operatively connected to said wheel, and a dash pot connectionbetween the lever arm and standard for retarding movements of the leverarm during pulling force thereof on the string puller.

5. In a racket stringing apparatus, wherein a racket supporting head ismounted upon the upper end of a standard, and wherein the string istensioned by sections with a tensioned string section held under tensionwhile tensioning another section, string tensioning means including astring puller slidably mounted on the upper end of the standard formovements transversely thereof, and a slide rod movable therewith, awheel journaled in the upper end of the standard, a flexible elementanchored at one end to the rod and anchored at its other end to the,wheel to be partly wound thereon and means for string puller.

6. In a racket stringing apparatus, wherein a racket supporting head ismounted upon the upper end of a standard, and wherein the string istensioned by sections with a tensioned string section held under tensionwhile tensioning another section, string tensioning means including astring puller slidably mounted on the upper end of the standard formovements transversely thereof, and a slide rod movable therewith, a

wheel journaled in the upper end of the standard, a flexible elementanchored at one end to the rod and anchored at its other end to thewheel to be partly wound thereon and means for rotating the wheel towind the flexible element thereon to move the rod and string puller forplacing a string under tension, including an adjustably weighted leverarm, a flexible member passing over said wheel with one end attached tothe weighted lever arm, manually operable means including a footoperated lever frame pivotally mounted at the lower end of the standardto which the other end of the flexible member is attached for moving thestring puller in a string releasing direction of movement against theaction of the weighted lever arm, and means for retarding movements ofthe weighted lever arm during pulling force thereof on the stringpuller.

EDMUNDO H. SERRANO.

